It took awhile, but I somehow managed to complete it in 44.7 seconds.
- Skate forward and grab the first bearing without grinding.
- Turn left and grind the outside of the rail, the transfer will register without needing to hop over.
- The speed should be enough to get you to the top bearing.
- Once you start reversing back down the rail, hop off and jump to the inside of the rail.
- Upon reaching the bench, hold left to roll off the edge, don't jump, and you should be able to exit the grind with some luck.
All this might be obvious to you already, but maybe it might help.